1. Field Of The Invention
The present invention relates to a novel yeast culture medium and to an assimilation test procedure employing such medium which is useful in conjunction with known conventional procedures presently employed to identify specific clinically significant species of yeast in an unknown isolate. The procedure of the present invention is particularly useful in distinguishing Candida parapsilosis from other Candida species and Cryptococcus neoformans from other Cryptococcus species.
2. Description Of The Prior Art
Conventional methods utilized to identify yeasts include tests for assimilation of carbohydrates, nitrogen sources, and in some instances, fatty acids or alkanes along with a variety of other tests.
The ability of yeasts and other fungi to metabolize phenolic compounds has been regarded as unique characteristic of certain isolates that might be exploited for reducing the phenolic content of sewage and other waste materials. J. Gen. Microbiol, 20:13-23 (1959); Sven. Papperstidn. 72:531-536 (1969); Nature, 195:473-474 (1962); J. Gen. Microbiol., 26:149-154 (1961) and Antonie van Leevwenhoek, J. Microbiol. Serol., 37:303-312 (1971). However, these references fail to teach or suggest the utilization of a particular phenolic compound as a sole carbon-source in a culture medium utilized in procedures for differentiating yeast species.
Kunze, Experientia, 24:844-845 (1968), identified nine phenolic compounds derived from the decomposition of lignin, including vanillin (4-hydroxy-3-methoxybenzaldehyde), vanillic acid (4-hydroxy-3-methoxybenzoic acid), 4-hydroxybenzaldehyde, PHBA (4-hydroxybenzoic acid), ferulic acid (4-hydroxy-3-methoxycinnamic acid), coumaric acid (4-hydroxycinnamic acid), protocatechuic acid; PCA (3,4-dihydroxybenzoic acid), caffeic acid (3,4-dihydroxycinnamic acid), and gallic acid (3,4,5-trihydroxybenzoic acid). However, no utility was disclosed or suggested for the compounds identified by Kunze.